I hate confirming the stereotype that Americans are ignorant of how things are done in the rest of the world, but apparently you guys don't know our system either. In the US, 3720:1 means that you can conquer Russia 3721 times and only be driven out once. Apparently, the rest of the world things differently.

Ever heard of Operation: Downfall? It was the planned alternative to nuclear strike - an all-out joint invasion of Japan by the United States and the Soviet Union. The total destruction from Operation: Downfall would have caused many more deaths (American, Russia, and Japanese) than the two nuclear strikes. Based on what we knew about the Japanese military culture at the time, they would not have surrendered until we were march down on the emperor himself, and they may have fought on after that. According to estimates, the atomic bombs saved more lives than they took.
(As far as fallout, the US military can claim ignorance on that one. Nuclear weapons were not fully understood at the time, and we needed to end the war quickly.)